Electric program switch for automatic appliances

ABSTRACT

A program switch, e.g. for a washing machine, has a rotating platter with cam tracks on both sides sandwiched between two pairs of contact carriers. Each contact carrier is a flat body of insulating material with a multiplicity of contact strips imbedded therein, these strips being originally part of a continuous metal foil coated on both sides with insulation. The contact strips of one plate of each pair terminate in a set of projecting tabs while those of the companion plate may remain interconnected and are tied to a supply conductor. The free ends of one set of contact strips of each pair project into cutouts of the respective plates and carry projections in engagement with the associated cam tracks for movement relative to the exposed tips of co-operating strips of the other set.

United States Patent 1191 111 3,725,618 Voland et a]. [4 1 Apr. 3, 1973[541 ELECTRIC PROGRAM SWITCH FOR 3,330,917 7/1967 Grundfest ..200/38 RAUTOMATIC APPLIANCES 3,003,097 10/1961 Jennings ...200/37 A X 3,239,6293/1966 Lesser ..200/166J x Inventorsr Dieter Voland, Georgen; Erich3,339,033 8/1967 Gable Blal ..200/38RX Scheer, Peterzell, both ofGermany Primary Examiner-C. L. Albritton [73] Assignee: Kieninger andObergtell, Georgen 32 i i g z R'peterson im Schwarzwald,Germany omey at05s [22] Filed: Aug. 27, 1970 [57] ABSTRACT [21] Appl. No.: 67,377 i Aprogram switch, e.g. for a washing machine, has a rotating platter withcam tracks on both sides sand- F P D wiched between two pairs of contactcarriers. Each [30] App'catmn am contact carrier is a Hat body ofinsulating material Sept. 3, 1969 Germany ..P 19 44 648.1 with amultiplicity of Contact strips imbedded therein. these strips beingoriginally part of a continuous metal 52 U.S. Cl. ..200/46, 200/38 0foil coated on both Sides with insulation- The Contact 51 Int. Cl...H0lh 43/08 Strips of one P1ate of each P terminate Set of 5 Field ofSearch 200 4 1 A 6 R 6 B 6 C projecting tabs while those Of thecompanion plate 200/37 R 37 A 38 A 5 A B 3 B may remain interconnectedand are tied to a supply 38 conductor. The free ends of one set ofcontact strips of each pair project into cutouts of the respectiveplates and carry projections in engagement with the [56] References cuedassociated cam tracks for movement relative to the ex- UNITED STATESPATENTS posed tips of co-operating strips of the other set. 3,154,64510/1964 P1111616 ..200/38 c -10 Claims, 4 Drawing Figures PATENTEUAPRSI975 SHEET 1 0F 3 PATENTEDAPRIB I975 3 725,51

SHEET 3 [IF 3 Diefer Voland Erich Scheer INVENTORS.

Attorney ELECTRIC PROGRAM SWITCH FOR AUTQMATIC APPLIANCES Our presentinvention relates to a program switch for automatic appliances such aswashing machines, dryers or dish washers.

Such program switches generally include a rotatable platter carried on ausually vertical shaft which, in the course of an operating cycle of theappliance, performs 1 revolution or a fraction thereof and which carriesa number of cam tracks coacting with associated switch contacts indifferent angular positions.

Especially with relatively complex switching circuits including a largenumber of contacts to be closed and opened in a predetermined sequence,the mounting of these contacts in operative relationship with theplatter requires considerable space which increases the bulk of themachine. Also, the wiring of these contacts either inside or outside theplatter housing becomes a laborious task and, unless painstakinglyperformed by skilled personnel, may easily lead to faulty connectionsand resulting malfunctions.

It is, therefore, the general object of our invention to provide animproved contact assembly for such program switches which avoids theaforestated drawbacks.

More particularly, our invention aims at providing a .compact andself-contained unit including all the necessary contact elements andassociated conductors for establishing the desired circuits between acommon voltage source and a large number of freely accessible terminalsto be selectively energized and de-energized.

These objects are realized, in accordance with our present invention, bythe provision of at least one pair of flat stationary contact carrierseach including a plate-shaped body of insulating material, preferably asynthetic resin; having an array of coplanar metal strips imbeddedtherein, each body having at least one cutout exposing portions of theimbedded strips for the establishment of conductive contact with similarstrips projecting into an aligned cutout on the other contact carrierupon close juxtaposition of the two insulating bodies. Thus, the alignedcutouts of the two bodies contain conductive elements togetherconstituting a number of pairs of coacting switch contacts,'one elementof each contact pair being a resilient leaf which carries an extensionpreferably of non-conductive (e.g. plastic) material projecting throughits own cutout or possibly through both cutouts toward the cammingsurface of the adjoining platter for alternate engagement with anddisengagement from its companion element under the control of the trackassigned to it. The two juxtaposed contact carriers may be permanentlybonded to each other, e.g. by thermal fusion if their insulating bodiesconsist of thermoplastic material.

In accordance with another feature of our invention, all the conductorstrips of either contact carrier are originally part of a continuousmetal foil to which the surrounding insulation is applied by anyconventional technique such as spraying or molding. Once continuity hasbeen assured by the hardening of the adhering insulating material,portions of the metal foil are cut away to establish the desired circuitlayout. The removal of the unwanted foil portions is facilitated byleaving at least one side of the foil accessible through omission ofcorresponding portions of the dielectric layer covering that side. Thus,it is particularly advantageous to design the original foil not as asolid sheet but as a perforated grid with a number of substantiallyparallel strip zones interconnected by transverse links integraltherewith. At the locations of these links the covering insulating layeris omitted so that the links can be readily severed by a cutting tool.For a given circuit arrangement, therefore, the tool may be a die with anumber of cutting edges registering with all the locations where suchseverance is to be carried out, the use of such a tool positivelyeliminating any error in the positioning and the interconnection of theconductor strips.

In one of the two juxtaposed contact carriers, some or all of theconductor strips may be left permanently interconnected for energizationin parallel from a supply lead connected to the foil, the strips of theother contact carrier then terminating in respective tabs which projectmarginally from its insulating body for engagement by wire clips,binding posts or similar connectors. The junction between the foil ofthe first body, serving as a live bus bar, and its supply lead may be inthe form of a slit in that foil bounded by two resilient tonguesintegral therewith, these tongues being adapted to grip a plug insertedinto a slit through a hole in the insulating body. Such a slit in astrip of one carrier may also be used for a semipermanent conductiveconnection with an aligned strip in the other carrier,

. either by letting an outwardly bent extremity of the latter stripenterthat slit or by forming the second strip with a similar slit sothat a conductive bridge piece may be inserted into the two slits. Sucha semipermanent connection may be useful, for example, if not all thenecessary terminal tabs can be accommodated on the carrier confrontingthe live bus bar so that one or more strips in the last-mentionedcarrier, insulated from the remaining strips, are utilized for an outputconnection. The slit may be formed by a complete transverse separationof the strip into two portions with confronting ends bent out of theplane of the strip to form the tongues.

The above and other features of our invention will be described indetail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is a side-elevational view, partly in section, of a contactassembly representing a program switch embodying our invention;

FIG. 2 is a top plan view, with parts broken away, of the assembly ofFIG. 1; and

FIGS. 3 and 4 are plan views, generally similar to FIG. 2, drawn to asmaller scale and showing two possible extensions of the arrangement ofFIGS. 1 and 2.

In FIG. 1 we have shown a shaft 1 which is driven from a nonillustratedmotor, either continuously or intermittently under the control of atimer, to cause the programmed closing and opening of circuits servingan associated washing machine or similar appliance. Shaft 1 carries aplatter 2 and is journaled in bearings 3 and 4 of the cover 6 and thebottom 5 of a housing 7 of nonconductive material.

Each side of platter 2 is provided with a series of cam tracks which maybe in the form of arcuate grooves centered on the shaft 1, parts of suchgrooves being visible at 31 on the upper platter surface and at 131 onits lower surface. Each of these surfaces confronts a respective pair ofjuxtaposed contact carriers 8, 9 and 10, 11 separated by a smallclearance from the platter,

each contact carrier being a flat dielectric plate of rectangular shapeas particularly illustrated for the uppermost plate 8 in FIG. 2.Imbedded in the insulating bodies of carriers 8 11 are metallic strips12, 13, 14 and 15, respectively, of good electrical conductivity. Eachset of strips is initially part of a continuous foil of grid-likestructure; the original contours of matrix 13 of plate 9' are visible indotted lines in FIG. 2. The pattern of this matrix is seen to be formedby a multiplicity of perforations 17, most of them rectangular, whichsubdivide the foil into two mutually orthogonal groups of generallyparallel strip zones partly indicated at 19 and 20. These strip zonesare interconnected by integral cross-links 18 so as to form, initially,an electrically continuous network whose constituents are then separatedfrom one another by a severance of these links. Thus, as shown in FIG.2, the upper insulating layer of plate 9 may be omitted at areas 51overlying the links 18 whereby the latter may be cut, as indicated at18', to interrupt the current path between adjoining strip zones.Extensions 21 28 of these strip zones form part of a connection betweenthe contact strips proper and a set of terminal tabs 29 projecting froman edge of plate 9; similar terminal tabs, not shown, are integral withthe conductor array of the bottom plate 11 of the lower stack.

Each of the four plates 8 11 is formed with a set of generallyrectangular cutouts 46, 47, 48 and 49 accominodating projecting ends 16,33, 38 and 39 of conductor strips 12 15, respectively. Strip portions 33and 39 are passive contacts and may be relatively rigid. Strip portions16 and 38 are active contacts of a highly elastic metal and areresiliently movable in their cutouts under the control of associated camtracks 31, 131 which they engage by means of wedge-shaped lugs 30, 130of insulating material molded onto their tips; The interengagingextremities of the strips may be provided with conventional blobs ofcontact material applied thereto mechanically or by thermal bonding.

It will be noted from FIG. 2 that each cutout 46 of plate 8 accommodatesthree parallel contactsprings 16 which are extensions of the imbeddedconductor array and are separated from one another by bar-shapeddividers 37 of insulating material integral with the body of the plate.FIG. 1 shows that these dividers rise to the level of the lid 6 whilesimilar dividers 137 of plate 11 extend to the housing bottom 5, therebycontributing to the mechanical stability of the assembly. Whenever astrip 16 is cammed out of engagement with its countercontact 33 by theedge of a groove 31 acting upon the lug 30, a knee 32 of that striprises above the top of plate 8 into the space separating it from lid 6.The presence of the dividers in that space prevents undesirable contactbetween adjacent'strips 16 simultaneously deflected into thisopen-circuit position.

. Furthermore, the metal foils 12 and 13 originally imbedded in carriers8 and 9 are cut away along a marginal zone 36 around each cutout 46(except at the points where these foils connect with the correspondingcontact elements 16 and 33) to guard against accidental contact betweenthe mobile springs and the imbedded conductors.

Advantageously, in order to ensure strict maintenance of the mutualalignments of the two plates 8, 9

and l0, 11 of each stack, these plates are interconnected at some or allof their edges by adhesive bond ing or thermal fusion along a peripheralzone 35.

Whereas the movable contact springs 16 of plate 8 are shown bent towardcompanion plate 9 whose cutouts 47 are traversed by their lugs 30, adifferent arrangement is adopted for the stack 10, 11 whose upper plate10, proximal to the platter 2, carries the mobile or active contacts 38whereas the remote plate 11 holds the passive contacts 39. These lattercontacts have been shown partly dropped into the space separating plate11 from housing bottom 5 so as to increase the spacing between the freeends of elements 38 and 39 in the illustrated open-circuit positioninwhich the lug on the rectilinear spring 38 enters a track groove 131.A part of the downwardly bent portion of strip 39 is reinforced by asheath of insulating coating 40 integral with the body of plate 1 1.

Thus, conductors 16, 33 may serve as contacts for a control circuit ofrelatively low voltage whereas conductors 38, 39 may act as circuitbreakers for the highvoltage power supply feeding the drive motor of theappliance. The imbedded extension of each spring 16 is shown traversedby a slit bounded by two upturned, resilient tongues 32 integral withconfronting strip portions to act as gripper jaws for a bridge piece 34also engaged by the jaws 132 of an aligned slit in a juxtaposedconductor strip 13. The resulting coupling between the two stripsconstitutes a semipermanent connection for the continuous energizationof this particular conductor 13 from the source of voltage connected tothe network 12. The connection between the network 12 and its voltagesource. may be similarly established with the aid of one or more plugs,not shown, engaging in respective slits 32 of the same type (but withdownwardly converging tongues) through other openings in the insulatingbody 8. In like manner, the conductor array 14 of plate 10 may beconnected to its power supply with the aid of a plug gripped by a pairofupwardly converging tongues or jaws. A similar slit is formed in one ofthe conductors 15 of plate 11, the jaws 232 of this slit gripping adownwardly bent extremity 41 of contact spring 38.

The tongues or gripper jaws 32, 132, 232 may be produced concurrentlywith the gaps 18' (FIG. 2) by means of punching tools on the samediewhich severs the links 18. For low-voltage applications, the spacing ofthe tongues may be sufficient to insulate adjoining strips in theabsence of an interposed connector.

As shown in FIG. 3, a rotary switch member 44 (coplanar with platter 2)underlies the stack 8,9 to coact with two sets of contact pairs 43', 43"forming part of a reversing switch. The construction of switch contacts43, 43" may be generally similar to that of elements 16, 33 describedwith reference to FIGS. 1 and 2, these switch contacts being included inthe conductive arrays of carrier plates 8 and 9 by internal connectionsnot shown. FIG. '3 also shows more clearly than FIG. 2 the relativeorientation of the several sets of contact springs 16 with reference toplatter 2, the corresponding rectangular cutouts 46 being peripherallyarrayed about the shaft 1 so that their major edges (and therefore alsotheir springs 16) are tangent to an imaginary circle drawn about theshaft axis. All the contact springs 16 may be energized in parallelthrough their residual connections with matrix 12.

FlG. 4 shows a more elaborate arrangement including a second platter 45coacting with a further set of contact springs 16'.

It will thus be seen that we have provided a compact and flat contactassembly which, whether used on both sides of a grooved platter or onlyadjacent one surface thereof, occupies very little mounting space andrequires no external wiring. Any defective unit can be instantlyreplaced by another unit manufactured by the same mass-productionprocess. Certain contacts of such a unit may also be used for thegeneration of pulses under the control of a rapidly rotating cam similarto reversing switch 44..

We claim:

1. A program switch comprising a rotatable platter provided on at leastone surface with a set of cam tracks; and two flat stationary contactcarriers parallel to said platter permanently joined together andclosely juxtaposed on the side of said surface, each of said contactcarriers including a plate-shaped body of insulating material with atleast one cutout and with an imbedded array of coplanar metal stripsprojecting into said cutout, the cutouts of said contact carriersregistering with each other to enable conductive interengagement ofexposed portions of pairs of coacting metal strips, the exposed portionof one strip of each coacting pair being a resilient leaf provided witha formation projecting through at least one of the aligned cutouts intocontact with a corresponding cam track on said surface for alternateengagement with and disengagement from the other strip of the pair, themetal strips of one of said contact carriers terminating in tabsprojecting marginally from the body thereof, the metal strips of theother of said contact carriers being part of a continuous foil, saidfoil being provided with an intermediate slit bounded by two resilienttongues integral with the foil, the body of said other of said contactcarriers having a hole aligned with said slit for insertion of a plugengageable by said tongues.

2. A program switch as defined in claim 1 wherein a metal strip of onecontact carrier has an extremity bent toward the other contact carrier,the latter having an overlying strip formed with an intermediate slitpenetrated with frictional engagement by said extremity.

3. A program switch as defined in claim 1 wherein two metal strips insaid contact carriers are provided with aligned intermediate slits,further comprising a conductive bridge piece frictionally received inboth said slits.

4. A program switch as defined in claim 1 wherein said contact carriersare bonded together along at least one common edge of their bodies.

5. A program switch as defined in claim 1 wherein the strip carryingsaid formation is part of the contact carrier remote from said platterand is bent at said leaf toward said platter into a cutout of thecontact carrier proximal to the platter.

6. A program switch as defined in claim 1 wherein the strip carryingsaid formation is part of the contact carrier proximal to the platterand is substantially straight within its cutout, a confronting portionof the coacting strip on the contact carrier remote from said cutoutbeing bent outwardly in the direction away from said platter.

7. A program switch as defined in claim 6 wherein metal strips in saidoffset portions connected in circuit 1 with at least some metal stripscontrolled by the cam tracks of said platter.

9. A program switch comprising a rotatable platter provided on at leastone surface with a set of cam tracks; and two flat stationary contactcarriers parallel to said platter permanently joined together andclosely juxtaposed on the side of said surface, each of said contactcarriers including a plate-shaped body of insulating material with atleast one cutout and with an imbedded array of coplanar metal stripsprojecting into said cutout, the cutouts of said contact carriersregistering with each other to enable conductive interengagement ofexposed portions of pairs of coacting metal strips, the exposed portionof one strip of each coacting pair being a resilient leaf provided witha formation projecting through at least one of the aligned cutouts intocontact with a corresponding cam track on said surface for alternateengagement with and disengagement from the other strip of the pair, ametal strip of one contact carrier having an extremity bent toward theother contact carrier, the latter having an overlying strip formed withan intermediate slit penetrated with frictional engagement by saidextremity.

10. A program switch comprising a rotatable platter provided on at leastone surface with a set of cam tracks; and two flat stationary contactcarriers parallel to said platter permanently joined together andclosely juxtaposed on the side of said surface, each of said contactcarriers including a plate-shaped body of insulating material with atleast one cutout and with an imbedded array of coplanar metal stripsprojecting into said cutout, the cutouts of said contact carriersregistering with each other to enable conductive interengagement ofexposed portions of pairs of coacting metal strips, the exposed portionof one strip of each coacting pair being a resilient leaf provided witha formation projecting through at least one of the aligned cutouts intocontact with a corresponding cam track on said surface for alternateengagement with and disengagement from the other strip of the pair, twometal strips in said contact carriers being provided with alignedintermediate slits, further comprising a conductive bridge piecefrictionally received in both said slits.

1. A program switch comprising a rotatable platter provided on at leastone surface with a set of cam tracks; and two flat stationary conTactcarriers parallel to said platter permanently joined together andclosely juxtaposed on the side of said surface, each of said contactcarriers including a plate-shaped body of insulating material with atleast one cutout and with an imbedded array of coplanar metal stripsprojecting into said cutout, the cutouts of said contact carriersregistering with each other to enable conductive interengagement ofexposed portions of pairs of coacting metal strips, the exposed portionof one strip of each coacting pair being a resilient leaf provided witha formation projecting through at least one of the aligned cutouts intocontact with a corresponding cam track on said surface for alternateengagement with and disengagement from the other strip of the pair, themetal strips of one of said contact carriers terminating in tabsprojecting marginally from the body thereof, the metal strips of theother of said contact carriers being part of a continuous foil, saidfoil being provided with an intermediate slit bounded by two resilienttongues integral with the foil, the body of said other of said contactcarriers having a hole aligned with said slit for insertion of a plugengageable by said tongues.
 2. A program switch as defined in claim 1wherein a metal strip of one contact carrier has an extremity benttoward the other contact carrier, the latter having an overlying stripformed with an intermediate slit penetrated with frictional engagementby said extremity.
 3. A program switch as defined in claim 1 wherein twometal strips in said contact carriers are provided with alignedintermediate slits, further comprising a conductive bridge piecefrictionally received in both said slits.
 4. A program switch as definedin claim 1 wherein said contact carriers are bonded together along atleast one common edge of their bodies.
 5. A program switch as defined inclaim 1 wherein the strip carrying said formation is part of the contactcarrier remote from said platter and is bent at said leaf toward saidplatter into a cutout of the contact carrier proximal to the platter. 6.A program switch as defined in claim 1 wherein the strip carrying saidformation is part of the contact carrier proximal to the platter and issubstantially straight within its cutout, a confronting portion of thecoacting strip on the contact carrier remote from said cutout being bentoutwardly in the direction away from said platter.
 7. A program switchas defined in claim 6 wherein part of said outwardly bent portion iscovered with insulation integral with the body of said remote contactcarrier.
 8. A program switch as defined in claim 1 wherein said contactcarriers have portions offset from said platter, further comprising aswitch member substantially coplanar with said surface positioned toengage metal strips in said offset portions connected in circuit with atleast some metal strips controlled by the cam tracks of said platter. 9.A program switch comprising a rotatable platter provided on at least onesurface with a set of cam tracks; and two flat stationary contactcarriers parallel to said platter permanently joined together andclosely juxtaposed on the side of said surface, each of said contactcarriers including a plate-shaped body of insulating material with atleast one cutout and with an imbedded array of coplanar metal stripsprojecting into said cutout, the cutouts of said contact carriersregistering with each other to enable conductive interengagement ofexposed portions of pairs of coacting metal strips, the exposed portionof one strip of each coacting pair being a resilient leaf provided witha formation projecting through at least one of the aligned cutouts intocontact with a corresponding cam track on said surface for alternateengagement with and disengagement from the other strip of the pair, ametal strip of one contact carrier having an extremity bent toward theother contact carrier, the latter having an overlying strip formed withan intermediate slit penetrated wiTh frictional engagement by saidextremity.
 10. A program switch comprising a rotatable platter providedon at least one surface with a set of cam tracks; and two flatstationary contact carriers parallel to said platter permanently joinedtogether and closely juxtaposed on the side of said surface, each ofsaid contact carriers including a plate-shaped body of insulatingmaterial with at least one cutout and with an imbedded array of coplanarmetal strips projecting into said cutout, the cutouts of said contactcarriers registering with each other to enable conductiveinterengagement of exposed portions of pairs of coacting metal strips,the exposed portion of one strip of each coacting pair being a resilientleaf provided with a formation projecting through at least one of thealigned cutouts into contact with a corresponding cam track on saidsurface for alternate engagement with and disengagement from the otherstrip of the pair, two metal strips in said contact carriers beingprovided with aligned intermediate slits, further comprising aconductive bridge piece frictionally received in both said slits.